Clothes drier



Dec. 2, 1952 P. E. GELDHOF ET AL 2,619, 7

CLOTHES DRIER Filed Jan. 51, 1951 4 Sheets-Sheet l IIiZI EWZUTE- Peter Eauara GeZofzof Hare/0 Morrison Dec. 2, 1952 P. E; GELDHOF ET AL 2,619,737

I CLOTHES DRIER Filed Jan. 31, 1951 4 Sheets-Sheet 2 157KB TYZE T5 Pei'er Eduard Geiahof' Harold E. Morrison Dec. 2, 1952 I E. GELDHQF Em 2,619 737 CLOTHES DRIER Filed Jan. 31, 1951 I 4 Sheets-Sheet 3 Fig.5

Peter Eduard Geld/10f H'a "01d Morrison- E E7 ,W/W .5 H7 75 Dec. 2, 1952 P. E. GELDHOF' ETAL CLOTHES DRIER 4 Sheets-Sheet 4 Filed Jan. 31, 1951 57 FE i I'm z' 5 Peter Eduard Geld/10f Harald E. Morrison b 1.5; Hit-54E" Patented Dec. 2, 1952 St. Joseph, Mich assign'ors to- Whirlpool oerporation, St. Joseph, Micli., a corporation of Michigan Applicationianuary 31, 1951, Serial No. 208,707

12 Claims. (01 34-133 This invention relates to improvements in clothes driers of the household typev where, clothes are tumbled in a. rotating drum, throu h which heated air is circulated.

One of the objects of our invention is to pro,- vide a new and improved form of rotating drumtype clothes drier having a positive forced air supply to the drum, at all times during opera,- tion of the drum.

Another objectof our invention is to provide an efficient and compact form of household type clothes drier arranged with a view toward utmost eiliciency in operation with an increased drying speed over former driersof the household type.

A further object of our invention is to provide a rotating drum type of household clothes drier wherein heated air is positively forced into the drier drum and the moist spent air is positively withdrawn therefrom, so as to provide a safer operating clothes drier eliminatingthe need for insulation, and atthe same time increasing, the speed, of the drying operation.

Another important object of our invention is to: provide a new and improved formof household rotating drum-type of clothes drier arranged with a view toward more uniform opera,- tion, regardless of variations: in the drum sealing parts thereof; T I

Heretofore, rotating drum-type clothes driers manufactured. for household. use have circulated the air into: and out of the drier drum through a bulkhead confronting aperi orate wall of the drumv and sealed thereto. Witli'such types of driersthe: drum. itself must be insulated toretain the heat therein and. a single blower has heretofore been provided to withdraw the moist spent air from the drum and'exhaust it to the atmosphere and also to draw the: air into the drum through louvers in the wall or the drier cabinet.

With such types of driers, if the: belt driving the .blower and drier drum should be broken while the drier is in operation, the drum itself may bethe heating element into the drum through the bulkhead and driven directly by the motorwhich drives the drier drum, and the other exhausting the spent air from the drier drum to the atmosphere and driven by the belt driving the drier drum. We thus provide a machine which will readily pass all Underwriters Laboratories tests, for when the belt driving the exhaust blower and drier drum is broken, while the drive motor for the drum is still operating the blower directly connected with the drive motor will draw air into the casing at room temperature and will force the air through the drum and positively exhaust it to the atmosphere, with the result that the drum may be stationary for an unlimited period without the danger of overheating the machine and causing a fire, as long as the motor is in operation.

These and other objects of our invention will appear from time to time as the following speci- "fl c'ation proceedsand with reference to the accompanying drawings wherein:

Figure l is. a transverse sectional view taken through a drier constructed in accordance with our invention;

Figure 2 is a vertical sectional View taken throughthe drier cabinet and looking at the rear end of the drum iIl'OIdGI to show the air circulating ducts and the drive for the drier drum;

Figure 3 is a front view of the drier with the cabinet removed, looking at the clothes-receiving end of the drier drum; and Figure 4 is a top plan view of the drier with the casing therefor removed. Y

In the embodiment of our invention illustrated in the drawings, the drier includes generally-a cabinet l0 mounted on and extending upwardly from a base I I and enclosing a drier drum l2 and the operating parts of the machine. The base ll may be adjustably mounted on feet 13-43 in order to afford a means to level the drier where the floor may be uneven.

A front wall I5"of the cabinet ID has a clothesreceiving opening I6 therein, which is defined by an inwardly extending flange IT. The flange I1 is shown" as extending toward the drier drum l2 and is then bent to extend at right angles toward the center of said drier drum to form a sealing shoulder la. The flange is then bent inwardh to form a second annular flange l9, coaxial with the axis of rotation of said drier drum and rolled over at its inner end to prevent tearing of the clothes? when being inserted or removed from the drier. A door 21 is hinged to thewall 15 and closes the opening I 6 during the drying opera- .tion.. A- sea-1mg member 23; on the door 21 is shown as engaging the inner edge of the inwardly extending portion of the flange I! to prevent heated air from escaping through said opening in said casing during the drying operation. The hinged mounting for the door 2| on the front wall l5 of the cabinet l9 may be like that shown and described in our application Serial No. 91,358, filed May 4, 1949, and entitled Electrically Heated Drier and is in no part of our present invention so need not herein be shown or described in detail.

The drum has a cylindrical wall which terminates at its front end into a frusto-conical wall 26, herein shown as being a separate annular piece and having an annular wall 21 extending inwardly from the inner or front margin thereof and forming the front wall of the drier drum. The annular front wall 21 terminates at its inner end into an outwardly curved flange 29 having a flexible sealing member 39 secured thereto and engaging the inner side of the inwardly extending shouldered portion l8 of the flange IT. This provides an air-tight seal between the front wall of the drum and the front wall of the cabinet during the clothes drying operation and prevents the escape of air from the front of the drier drum into the cabinet and thus prevents the recirculation of damp warm air containing lint through said drier drum.

A rear wall 3| of the drier drum I2 is provided with an annular opening 33 having a screen 34 extending therearound and suitably secured thereto and forming a perforate rear wall for the drier drum |2 for the introduction of air into said drum and the exhaust of spent air therefrom.

The rear perforate wall 3| of the drum I2 is reinforced by means of a plurality of arms 35-35, herein shown as being three in number, secured at their outer ends to the inside of the cylindrical wall of the drum I2. The arms 3535 curve inwardly and extend along the perforate wall 3| and are secured at their inner ends to a hub 36. The hub 36 is secured to and. rotated by a transverse shaft 31. hub 36 and the end of the shaft 31 to protect the clothes from said hub and shaft and is suitably secured at its outer side to the inner margin of the screen 34.

The transverse shaft 31 is journaled within a bearing sleeve 39 mounted adjacent one of its ends on a bulkhead 40. The bulkhead 45 is mounted on the base H and extends upwardly along the perforate rear wall 3| of the drum l2. The bearing sleeve 39 is likewise supported on a wall 4| of a channel-like support member 43 mounted on and extending upwardly from the base The channel-like support member 43 abuts the bulkhead at the forward ends of its legs and may be suitably secured thereto to form a rectangular box-like support with said bulk- -head and thus form a rigid support for the bearing sleeve 39 and drier drum I2.

A pulley 44 is secured to the outer end of the shaft 31 to rotatably drive the drier drum l2. A motor 45 having a motor shaft 46 is mounted on the base at one side of the cabinet and beneath the major portion of the drum |2 to drive said drum. A pulley 41 on the motor shaft 46 drives a pulley 48 on a shaft 49 spaced beneath the motor shaft 31 at a reduced speed of rotation and drives a pulley 50 at the speed of rotation of the pulley 41 by means of a belt 5| which may be of a well known form of V-belt. The pulley 44 is driven from the pulley 49 at a further reduced A circular plate 38 encloses the '4 speed of rotation by means of a pulley 53 coaxial with and driven from the pulley 49 and a V-belt 54 trained around the pulleys 53 and 44.

The shaft 55 on which the pulley 59 is secured is herein shown as being a shaft of a fan or blower 55 contained within an exhaust air duct 51 secured to the back of the bulkhead 4t. Said exhaust air duct extends upwardly along the back of said bulkhead to a duct 59 leading rearwardly therefrom to and through a rear wall B0 of the cabinet l9 to exhaust air to the atmosphere.

The blower 56 may be of any well known form and is herein shown as being a radial vane type of blower suitably mounted on the rear side of the bulkhead 40 in association with an exhaust opening 6| formed'therein. The exhaust opening 6| confronts the annular perforate wall 33 of the drier drum l2 and the blower 6| serves to positively exhaust air therefrom during rotation thereof. 7

The rear wall 3| of the drum I2 is sealed at the periphery of the drum with the bulkhead 49 to assure the circulation of air into and out of the drum through its rear wall and the bulkhead by a sealing member 63 of an annular form which may be secured to the cylindrical wall 25 of the drum l2 and have wiping engagement with the forward wall of the bulkhead inwardly of an inturned flange 64 of the bulkhead. The flange 64 extends along the upper margin of the bulkhead 40 toward the drum and is made from asbestos or any other suitable heat-resistant sealing material.

It should here be noted that the bulkhead 40 stops short of the top and side walls of the cabinet l0 and is sealed to the rear wall of the drum at its periphery to allow the incoming air to circulate around the drier drum, but to prevent the heated air from escaping from the drum or bulkhead to the inside of the cabinet and thus preventing the discharge of the moist spent air within the cabinet where it may be carried back through the air circulating system into the drum.

The bulkhead 40 likewise has an intake opening 66 formed therein confronting the annular open portion 33 of therear wall 3| of the drier drum I2 through which heated air may be forced into said drier drum. An intake air duct 61, herein shown as being vertically extending, communicates at its upper end with the intake opening 66 and extends upwardly along one side of the bulkhead 40 from the lower end thereof. The intake air duct 61 is herein shown as having'a heating element 69 therein. The heating element 69 is shown as being a well known form of coil type electrical heating element and may be like that shown in our prior application Serial No. 91,358, filed May 4, 1949, and entitled Electrically Heated Drier, so need not herein be shown or described in detail.

It should here be understood that the intake air need not be electrically heated but may be heated by a gas burner if desired, as in our application Serial No. 123,018, filed on October 22, 1949, and entitled Gas Heated Drier.

Fresh air at room temperature is drawn into the cabinet through louvers Ill-13, herein shown as being in the rear wall thereof, by means of a blower or fan 13. The blower 13 is herein shown as being a radial vane type of blower mounted and driven from the opposite end of the motor shaft 46 from the pulley 41. The blower 13 is contained within a transversely extending air duct 14 at one end thereof. The duct 14 is herein shown as being mounted on the base and extendingthereacross from one side thereof to-the other to a positionadjacent the intake air duct 8L The transverse air duct 14 has an in-v take opening 15 therein confronting the intake side of the blower 13 and on the opposite side of said air duct from the motor 45. A conduit 16 connects the end of the transverse air duct I4 opposite from the motor 45 with the intake air duct adjacent the lower end thereof. It may be seen from the foregoing that the blower 13, being directly mounted on the motor shaft 46, is always in operation as long as the motor 45 is operating, and that since the blower is directly driven by said motor fresh air will be drawn into the cabinet through the louvers 10 and over the drum andwillbe forced into the rear perforate wall 33' of the drier drum I2, even though the belt 5| maybe broken and the drier drum itself may not be rotating. This protects the drier against becoming overheated in case the belt 51' should be broken while the heating coils 65- are-in operation by continually forcing tempered and heated air into the drum and forcing an equal volume of hot air from the drum. This construction thus assures a safe machine which will readily pass all requirements of the Underwriters Laboratories and will operate for an indefinite period with one or both of the belts driving the drier drum broken and with the heat turned on,

It may further be seen that when the blower is in operation and the door 21 is'closed, the blower 13' will-draw fresh air in through the louvers 10-10 upwardly along the rear side of the bulkhead 40 around'the outside of the drum and into the intake opening 15 of the air duct 14 facing the'front wall of the cabinet l0. It will also draw fresh air at room temperature over the motor and will maintain said motor cool. The fresh air at roomtemperature will thus accumulate heat from within the cabinet as itcirculates or flows around the outside of the drum and is drawn into the air duct 14 and forced to flow upwardly'around and past the heatingcoils 69 into the drier drum through the intake opening 6'5 in the bulkhead 34. The air heated by convection as it passes upwardly along the heater cells is forced into the drier drum and will pick up moisture as it circulates through the drier drum. and clothes, and will be positively exhausted from. the drum by the upper blower 5B in the exhaust air duct 51, which will positively exhaust the moist. spent air from the drier drum to the atmosphere through the rear wall 68 of the cab-- inet I0.

It may further be seen that the drier and circulating system just described forces the supply of fresh air through the drum at a rate and in a volume which may be predetermined according to drying requirements and the desired temperature of the clothes within the drum; that the air is partially heated by the drum as it is drawn. within the cabinehmaking it unnecessary to, insulate the drum and the heating element; and that the air being circulated within and through the drier drum is confined tothe drum and prevented from escaping into the cabinet or to the atmosphere through the front door thereof, enabling thetemperature of the drum to be lower and more readily controlled than formerly and permitting the operation of the drier at more accurate drum temperatures.

It will be understood that various modifications and variations of the present invention may: be

, efliected without departing" from the spirit and scope of the novel concepts thereof- We claimasour invention:

1... A. clothes. drier comprising a cabinet, a. drier drum rotatably mounted withinv said cabinet, said drumhaving a. perforate wall for the circulation of air therethrough, a bulkhead confronting-the perforate wall of said drum and. having a. plural!- ity of air circulating openings therein in com.- municationwith the perforate Wall of said drum, an air ductin communicationxwith. one opening. in said bulkhead, a. heating element: in said air duct, a blower drawing air into said cabinet through a wall thereof. and forcing. air to flow over said heating element into said drumthrough one of said openings, another air duct communicating with another opening insaid. bulkhead and leading outthrough a wall of said cabinet: to the atmosphere, and a blower associated with said last mentioned air ductto withdraw air from said drum and exhaust it to the atmosphere.v

2. In a clothes drier, a cabinet, a drier drum rotatably mounted in said cabinet, said drier drum having front and rear walls, one of' which is perforate for the circulation of air there.- through, abulkhead in said cabinet having a plurality of air circulating openings therein confronting the perforat wall' of said drum, sealing means sealing the periphery; of said drum with said bulkhead, an opening in said cabinet for admitting fresh air thereinto, a blower communicating with one of the openings. in said bulkhead for drawing fresh air into said cabinet and into said drum through said bulkhead, a second blower communicating with the other opening in said bulkhead for withdrawing air from said drum, and conduit means conducting air from said sec.- ond blower and drum to the atmosphere.

3. In a clothes drier, a cabinet, a. drier drum rotatably mounted in said cabinet, said. drier drum having front and rear walls, one of which is perforate for the. circulation of air there: through, a bulkhead mounted within said cabinet and extending along the perforate wall of said drum and having two air circulating openings therein registering with the perforate wall-of. said drum, sealing means sealing the periphery of said drum with said bulkhead, means admitting fresh air into said cabinet, an air duct extending along the rear of said bulkhead and communicating with one opening therein, a heating element in said air duct,.a blower drawing fresh air Within said cabinet and forcing it through said air duct over said heating element into said drum, 2. second air duct connected with the second opening in said bulkhead. and leading through a wall of said cabinet to the atmosphere, and a blower associated with said second air duct. and withdrawing moist spent air from said drum and exhausting it to the atmosphere through. said second air duct.

4. In a clothes drier, a cabinet, a drier drum rotatably mounted withinsaid cabinet and having front and rear walls, one of which is perforate for the circulation of air therethrough, a bulkhead mounted within said cabinet and extending along the perforate wall of said drum and having two air circulating openings therein registering with the perforate wall of said drum, sealing means sealing said drum with said bulkhead, an opening in a wall of said cabinet for the admission of fresh air thereinto, an air duct extending upwardly along the outer side of said bulkhead from the lower end thereof and communicating with the inside, of said cabinet; at its; lower end and with an opening in said bulkhead at its upper end, a heating element in said air duct, a blower communicating with said air duct and drawing fresh air in said cabinet and forcing it through said air duct over said heating element and into said drier drum, a second air duct extending from the outer side of said bulkhead and communicating with the second opening therein and leading from said bulkhead through a wall of said cabinet to the atmosphere, and a blower within said second air duct in communication with said other opening in said bulkhead for positively exhausting spent air from said drier drum to the atmosphere through said second air duct.

5. In a clothes drier, a cabinet, a drier drum rotatably mounted within said cabinet and having a perforate wall for the circulation of air therethrough, a motor within said cabinet and a drive connection from said motor to said drier drum, a bulkhead in said cabinet extending along the perforate wall of said drum and having two air circulating openings therein registering with the perforate wall of said drum, means sealing the periphery of said drum with said bulkhead, an air duct leading from one of the openings in said bulkhead out through a wall of said cabinet, a blower associated with said air duct for positively exhausting spent air from said drum to the atmosphere, a flexible drive connection from said motor to said drier drum and blower, an opening in a wall of said cabinet for the admission of fresh air thereinto, an air duct extending upwardly along the outer side of said bulkhead from the lower end thereof and connected with the other opening in said bulkhead at its upper end, a heating element in said air duct, a blower communicating with said air duct and drawing fresh air into said cabinet and circulating it around the drum and also forcing air through said air duct over said heating element into said drum through said bulkhead, and a direct drive connection from said motor to said blower.

6. A clothes drier comprising a cabinet, a drier drum mounted within said cabinet, a door within said cabinet affording access to the inte rior of said drum, said drier drumhaving a perforate air circulating wall, a bulkhead confronting the perforate wall of said drum and having a plurality of air circulating openings in communication with the perforate wall of said drum, means sealing the periphery of said drum with said bulkhead and providing an air-tight chamber therebetween, a fresh air intake opening in the wall of said cabinet, a blower mounted on said bulkhead in association with one of said openings therein, an air duct enclosing said blower and leading from said bulkhead through a wall of said cabinet, another air duct extending vertically along the outer side of said bulkhead from a position adjacent the lower end thereof and having communication with the other opening in said bulkhead, a heating element in said air duct, a blower associated with said air duct for drawing fresh air into said cabinet and forcing it to flow through said air duct over said heating element into said drum, a motor for rotatably driving said drier drum and blowers,

the connection from said motor to one of said blowers being a flexible drive connection and the connection from said motor to the other of said blowers being a direct drive connection.

'7. In a clothes drier, a cabinet, a drier drum rotatably mounted within said cabinet and having a perforate wall for the circulation of air into and out of said drum, a' door in said cabinet affording a means of access into said drier drum, means sealing said drum with the front wall of said cabinet to prevent the passage of air thereby when said door is closed, a bulkhead confronting the perforate wall of said drum and having a plurality of air circulating openings therein in communication with the interior of said drum through said perforate wall, a blowerassociated with one of said openings in said bulkhead, an air duct enclosing said blower and leading from said opening out through a wall of said cabinet, another air duct extendingvertically along said bulkhead and having communication with another of said openings in said bulkhead, a heating element in said air duct, a transverse air duct extending across the bottom of said cabinet beneath the drier drum and having communication at one of its ends with said vertically extending air duct, a blower in the opposite end of said transversely extending air duct, an opening in the wall of said cabinet, and a single motor for driving said drier drum and blowers, the connection from said motor to said drier drum and one of said blowers including a flexible belt and the drive connection from said motor to the other of said blowers being a direct drive connection.

8. A clothes drier comprising a cabinet, a drier drum rotatably mounted within said cabinet, said drier drum having a front wall confronting a front wall of said cabinet and having a clothes receiving opening therein, a door in said cabinet closing said front wall of said drum, means for sealing said front wall with said cabinet, said drum also having a perforate air circulating rear Wall, a bulkhead extending vertically along the rear Wall of said drum and terminating adjacent the upper end of said drum beneath the top of said cabinet, means sealing the periphery of said drum with said bulkhead, an exhaust opening in said bulkhead confronting the perforate rear wall of said drum, a blower in said exhaust opening, an air duct enclosing said blower and leading from said exhaust opening through a wall of said cabinet, an intake opening in said bulkhead adjacent the opposite side thereof from said exhaust opening, an air duct extending along said bulkhead and having communication with said intake opening, a heating element within said air duct, and a blower positively drawingfresh air into said cabinet and forcing it to flow along said intake air duct over said heating element intosaid drier drum through said intake opening in said bulkhead.

9. In a clothes drier, a cabinet, a drier drum rotatably mounted within said cabinet and having a front wall having a clothes-receiving opening therein confronting a front wall of said cabinet and a perforate rear wall, a bulkhead having air circulating openings therein confronting the perforate rear wall of said drum and confining the circulation of air into and out of said drum through said perforate rear wall, a door in the front wall of said cabinet affording access to the interior of said drum, means sealing said clothesreceiving opening with the front wall of said cabinet and confining the circulation of air through said perforate rear wall when said door is closed, an intake air duct having a heating element therein associated with one of said openings in said bulkhead, an exhaust air duct leading through a wall of said cabinet and associated with the other of said openings in said bulkhead, a blower positively exhausting air from said drum, and another blower drawing fresh air in said cabinet and circulating the air around said drum and forcing the fresh air to blow over said heating element into said drum through said opening in said bulkhead.

10. In a cloth-es drier, a cabinet, a drier drum rotatably mounted within said cabinet and having a front wall having a clothes-receiving opening therein confronting a front wall of said cabinet and a perforate rear wall, a bulkhead having air circulating openings therein confronting the perforate rear wall of said drum and confining the circulation of air into and out of said drum through said perforate rear wall, a door in the front wall of said cabinet affording access to the interior of said drum, means sealing said clothesreceiving opening with the front wall of said cabinet and confining the circulation of air through said perforate rear wall when said door is closed, an intake air duct having a heating element therein ass ciated with one of said openings in said bulkhead, an exhaust air duct leading through a wall of said cabinet and associated with the other of said openings in said bulkhead, a blower positively exhausting air from said drum, a single motor within said cabinet, drive connections from said motor to said drum and one of said blowers, and another drive connection from said motor to the other of said blowers, the drive connection to one of said blowers being flexible and the drive connection to the other of said blowers being a direct drive connection.

1 In a clothes drier, a cabinet, a drier drum rotatably mounted Within said cabinet and having a front wall confronting a front wall of said cabinet and having a clothes-receiving opening therein and a perforate rear wall for the circulation of air into and out of said cabinet, a door in the front wall of said cabinet affording a means for access to the interior of said drum, sealing means sealing the periphery of said clothes-receiving opening in said front wall with the front wall of said cabinet, a bulkhead mounted within said cabinet and extending along the perforate wall of said drum and having two air circulating openings therein registering with the perforate wall of said drum, sealing means sealing the periphery of said drum with said bulkhead, an air duct extending upwardly along the outer side of said bulkhead adjacent one side of said cabinet and communicating with one of said openings in said bulkhead for conducting heated air therein, a heater within said air duct, a transversely extending air duct disposed beneath said drum and extending across the bottom of said cabinet from one end thereof to the other and communicating at one of its ends with said intake air duct, an intake opening in a wall of said casing, a blower at the opposite end of said transverse air duct from said intake air duct, drawing air into said cabinet and around said drum and forcing air to flow through said intake air duct over said heating element to said drum, an exhaust air duct leading 10 from the other opening of said bulkhead through a wall of said cabinet to the atmosphere, and a blower in said exhaust air duct positively exhausting air from said drum through said bulkhead to the atmosphere.

12. In a clothes drier, a cabinet, a drier drum rotatably mounted Within said cabinet and having a front wall confronting a front wall of said cabinet and having a clothes-receiving opening therein and a perforate rear wall for the circulation of air into and out of said cabinet, a door in the front wall of said cabinet affording a means for access to the interior of said drum, sealing means sealing the periphery of said clothes-receiving opening in said front wall with the front wall of said cabinet, a bulkhead mounted within said cabinet and extending along the perforate wall of said drum and having two air circulating openings therein registering with the perforate wall of said drum, sealing means sealing the periphery of said drum with said bulkhead, an air duct extending upwardly along the outer side of said bulkhead adjacent one side of said cabinet and communicating with one of said openings in said bulkhead for conducting heated air therein, a heater within said air duct, a transversely extending air duct disposed beneath said drum and extending across the bottom of said cabinet from one end thereof to the other and communicating at one of its ends with said intake air duct, an intake opening in a wall of said casing, a blower at the opposite end of said transverse air duct from said intake air duct, drawing air into said cabinet and around said drum and forcing air to flow through said intake air duct over said heating element to said drum, an exhaust air duct leading fro-m the other opening of said bulkhead through a wall of said cabinet to the atmosphere, a blower in said exhaust air duct positively exhausting air from said drum through said bulkhead to the atmosphere, a motor mounted within said cabinet, belt drive means from said motor to said drier drum and to one of said blowers, and a direct drive connection from said motor to the other of said blowers.

PETER EDUARD GELDHOF. HAROLD E. MORRISON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,255,162 Haney Feb. 5, 1918 1,358,599 White Nov. 9, 1920 1,733,785 Ernst Oct. 29, 1929 2,262,186 Lindberg Nov. 11, 1941 2,498,172 Mintner et a1 Feb. 21, 1950 2,521,712 Geldhof Sept. 12, 1950 FOREIGN PATENTS Number Country Date 620,905 Great Britain Mar. 31, 1949 

